Here is mentioned something about XP doing writes to the port:
http://www.lvr.com/jansfaq.htm
Quote:
Q: If a logic 1 is written to the Control Port, bit 0, (Strobe), the PC clears all of the port bits once every five seconds for about a minute.
A: Some versions of Windows XP look for devices by periodically writing to the port. A registry key can disable this behavior.
The following registry setting disables the port writes:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Parport\Parameters]
"DisableWarmPoll"=dword:00000001
The following registry setting enables the port writes:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Parport\Parameters]
"DisableWarmPoll"=dword:00000000
You can make these changes in Windows' regedit utility. Or to make the changes automatically, create and save the following text files:
DisableWarmBoot.reg contains the following text:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Parport\Parameters]
"DisableWarmPoll"=dword:00000001
EnableWarmBoot.reg contains the following text:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Parport\Parameters]
"DisableWarmPoll"=dword:00000000
To change a registry key, run the program.
As always, use caution when working with the registry, which contains critical values for configuring and running the PC.
After making a change, reboot the PC.
Disabling the port writes can also eliminate port timeout errors received in some applications.
Thanks to Richard Shotbolt for informing me of this fix.
I don't know if this has anything to do with it though.